Liberty Media plans to spin off the premium TV network in 2013 along with sister channel Encore. The move raises the stakes for Starz and its CEO.

Its shows have largely failed to attract the buzz that can drive subscriptions and ratings. "Spartacus" was Starz's most popular show, averaging more than 5 million viewers an episode during the third season when viewing on all platforms was counted. "Magic City," the channel's stylistic drama about Miami gangsters in the 1950s, averaged 3.1 million viewers an episode when it debuted this year, while "Boss" collared just 2.2 million an episode.

Starz is betting heavily on its lineup for next two years, which includes the second season of "Magic City" and the new prospects "Da Vinci's Demons," a drama about Leonardo's early days from David S. Goyer, a co-writer of the "Dark Knight Rises" film trilogy, and "Black Sails," a swashbuckling adventure from "Transformers" filmmaker Michael Bay.

The company this year is spending about $692 million on programming, with four-fifths of that amount earmarked for buying products from Disney and Sony Pictures Entertainment, according to SNL Kagan, which said Starz spends less than $100 million annually creating original series.

"They still need the movies to fill their schedule, but at the same time Starz needs some unique programs to define the channel," said Deana Myers, an SNL Kagan television analyst. "It's not an easy market to get into because a lot of other networks are doing original productions."

Although Starz will continue to receive the Disney movies for three years, the eventual loss puts pressure on the company to keep Sony as a supplier beyond2016, when the parties' current arrangement ends. The loss of Disney movies and the coming end of the Sony contract could also complicate the picture as Starz tries to attract a new owner.

Potential suitor Viacom already has a presence in the premium channel business. The parent of Paramount Pictures teamed in 2009 with two other studios, Lions Gate Entertainment Corp. and Metro-Goldwyn-Mayer Studios Inc., to launch the movie service Epix. The upstart has struggled to make distribution deals with leading cable and satellite TV systems. That could make a merger between Epix and Starz enticing. Given that Epix is not nearly as powerful as HBO and Showtime, such a deal may also be able to pass regulatory muster.